The Tea Party and the Occupy Wall Streeters owe a lot to a little fish called the golden shiner. Golden shiners are not very high on the aquatic food chain. They measure just 3 to 5 in. (7.5 to 12.5 cm) and serve as so tasty a finger food for bigger, more aggressive species that humans use them as bait fish. But the golden shiner can have strong opinions  deeply, fiercely held ones. And that, according to an improbable new study published in the journal Science, can tell us a lot about how American democracy works.

Social animals  schooling fish, flocking birds, herding ungulates, cable-news-watching humans  conform to what have always been thought to be some pretty simple behavioral patterns: the majority rules; the minority follows  unless the minority is unusually loud or absolutist. Then it can can exert an influence that belies its small size. This is especially true if you stir a third group  the uninformed or indifferent  into the mix. They are easy for the shouters and table bangers to persuade and can quickly turn the minority into a majority. Or at least, that has always been the go-to formula.
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An international team of researchers headed by evolutionary biologist Iain Couzin of Princeton University decided to test that assumption  and to use fish as a model electorate. Schooling fish love to be led. A computer model developed by biologist Simon Levin, also of Princeton, found that it can take just 5% of a school to start moving toward a food source for the other 95% to follow  even if they don't know where they're going. Couzin and his colleagues conducted the first part of their experiment with a computer model as well, but they developed a more complex one.

Beginning with the standard programming for fish behavior  with individuals tending to draw together and align their direction of travel, but not so closely as to collide  the investigators created a virtual school that contained two groups: a minority that was extremely committed to the direction in which it was swimming, and a majority moving in another direction but with less resolve. As predicted, the minority ruled, with the majority taking over only when its commitment was equal to or greater than that of the smaller group. When a third, uncommitted group was added, things changed, but not the way the standard models suggested. Rather than moving with the most insistent swimmers, they followed the larger, less driven group. The minority, even locked into its course, lost.

"In all models, an entrenched minority is capable of exerting substantial influence." the researchers wrote. "However, uninformed individuals will lend support to, and tend to amplify, a numerical advantage (even a slight one)."

Computer models, of course, can take you only so far, and this is where the researchers broke out the golden shiners. Like many fish, shiners tend to move toward light, and also like many fish, they prefer some colors over others. Shiners, as it happens, are partial to yellow. The investigators thus trained a few of them to gravitate toward blue  a preference they concluded would be less firmly held, since it deviated from the fishes' natural tendencies.
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The groups were small  with just six fish in the blue-light majority and five in the yellow-light minority  because of what the investigators called "the time-consuming nature of the training." (Golden shiners are not nature's brainiacs.) Still, when the fish were released into a tank and allowed to swim toward their choice of the two lights, the model held, with the minority controlling the group's overall direction. When a group of five untrained individuals was introduced, the computer's results were confirmed again: the newcomers voted with their feet, as it were, moving with the blue-light majority, even though that was not their natural tendency. When the untrained group was increased in size to 10, the preference became even stronger.

The implications for human political systems are, well, not entirely clear, though the modern history of both major U.S. political parties does show some distinctly fishlike behavior. The Democrats were yanked hard to the left by their most fevered liberals in the 1970s and were repeatedly punished for it by a more moderate electorate. The present-day GOP has been similarly taken over by its fire-breathing right and was crushed by the moderate middle in 2006 and 2008. While the Tea Partyers stormed Congress in 2010, many of their newly won seats are believed to be in jeopardy this time around, with voters increasingly rejecting ideological purity and demanding simple compromise instead.

None of this means that political strategists will begin focus-grouping fish any time soon. It does mean that whether we want to admit it or not, human beings  including Democrats and Republicans  are nothing but social animals and play by very similar rules. Hey, they don't call them donkeys and elephants for nothing.